People seem to forget that Kimlin absolutely tore the Lions apart at lineout and in the open for the Brumbies. And that was against Gray, Parling and Evans in the lineout, and O'Brien, Felatau and Lydiate in the back row. A lot of those are in the line up for this test.
Ben McC does not have that sort of form this year, nor whenever he played for the Wallabies in the past. Not a good selection imo.
Kimlin undoubtedly had an absolute blinder in the Brumbies game against the Lions. Whilst he has had an excellent season, using that one game purely as the benchmark for his form is also a bit misleading. He isn't that good every week.
For much of that game, the Lions hooker was Best who had an absolute shocker. Expecting someone who dominanted their lineout in that game to do the same against a much better performing hooker is also flawed.
I would have had no issue with Kimlin being selected but I figure the selection of McCalman is for the reliability he brings. I also only see him getting on the field if George Smith can't go 80 minutes.
I expect the first backrow substitution unless there is an injury is Hooper coming on for Palu and Mowen shifting to 8 (whether Smith shifts to 6 or Hooper plays there is somewhat unknown and probably not that relevant. Smith will be more focused on competing at the breakdown whichever position he is packing in the scrum).
Unless Smith is stuffed after 50 minutes and needs to be replaced by Hooper I expect we'll see both Hooper and Smith on the field at the same time. That will certainly be the plan.